Aqueous coating composition and coating method with use of the composition

Abstract

Disclosed is an aqueous coating composition characterized in that the composition consists essentially of: (A) a resin for use in aqueous coating compositions, (B) a urethane resin emulsion, and (C) crosslinking agent, the component (B) being an aqueous dispersion of a polyurethane resin prepared by reacting (a) an aliphatic polyisocyanate and/or an alicyclic polyisocyanate, (b) a high-molecular-weight polyol, (c) an α,α-dimethylolmonocarboxylic acid, and when required, (d) a chain lengthening agent and/or a polymerization terminator, and subsequently neutralizing the carboxyl with (e) a primary monoamine and/or a secondary monoamine.

We claim: 
     
       1. An aqueous coating composition characterized in that the composition consists essentially of: (a) a resin for use in aqueous coating compositions which is selected from the group consisting of hydroxyl- or carboxyl-containing acrylic resins, alkyd resins, epoxy resins and fluorine-containing resins,   (B) a urethane resin emulsion, and   (C) crosslinking agent,   the component (B) being an aqueous dispersion of a polyurethane resin prepared by reacting (a) an aliphatic polyisocyanate and/or an alicyclic polyisocyanate, (b) a high-molecular-weight polyol, (c) an αα-dimethylolmonocarboxylic acid, and when required, (d) a chain lengthening agent and/or a polymerization terminator, and subsequently neutralizing the carboxyl with (e) a primary monoamine and/or a secondary monoamine.   
     
     
       2. An aqueous coating composition as defined in claim 1 wherein the resin (A) is an acrylic resin.